Fluid pressure remote control system



Jul 9, 1940. s. M D. PARKER 2,207,491

FLUID PRESSURE REMQI'E CONTROL SYSTEM Fi1ed Nov. 17, 1939- sSheets-Sheet 1 INVENTOR.

h drygne y Mac D. Parker 2? af w July 9, 1940. 5. mm. PARKER 1 2,207,491

FLUID PRESSURE REMOTE CONTROL SYSTEM File d Nov. 17, 1938 s Sheets-Sheet 2 v R r 73 68 624735.51 3 34 I jmwroz.

Bar/fer Ame. razy July 9, 1940. 5. men. PARKER 2,207,491

-FI.|UID PRESSURE REMOTE-CONTROL SYSTEM Filed Nov. 17, 1938 asheetssneet s Patented July 9, 1940 UNITED STATES PATENT OFFICE SydneyMacdonald Parker,

England, assignor to Myton, Warwick, Automotive Products CompanyLimited, London,'England, a company of Great Britain ApplicationNovember 17, 1938, Serial No. 241,063 In Great Britain November 25, 19377 Claims.

This invention relates to fluid pressure remote control systems in whichthe pressure generated by a single pump or group of pumps is employedselectively to operate a plurality of fluid pressure responsive motorsperforming various services, as for example, on an aircraft where thereare numerous devices which are readily adapted for fluid pressurecontrol, such as the retractable undercarriage, flaps, brakes, bombdoors and hoists, l gun triggers and others.

One object of the invention is to provide a fluid pressure remotecontrol system for performing a plurality of services, in which certainservices of primary importance are so connected to the source ofpressure fluid that damage to the portions of the system controlling theremainin services cannot bring the system into a condition in which suchprimary services are put out of action.

Another object of the invention is to provide a fluid pressure remotecontrol system for performing one or more primary services and one ormore secondary services which comprises a pump delivering pressure fluidto fluid pressure responsive motors or pressure accumulators operatingthe main services, and also to pressure accumulators operating thesecondary-services, and a valve device operated by loss of fluid fromthe system to isolate from the pump the pressure accumulators supplyingthe secondary services.

still another object of the invention is to provide a fluid pressureremote control system comprising one or more pumps delivering pressurefluid to a common circuit, and motors or pressure accumulators receivingsaid fluid and serving to operate controlled devices, a part of thecircuit being divided into two branches, one of which supplies thepressure accumulators serving to operate certain of the controlleddevices, a valve device being provided which is operated by loss 40 offluid from the system to isolate from the circuit the branch supplyingsaid pressure accumulators. V

Another object of the invention is to provide a fluid pressure remotecontrol system co'mprising one or more, pumps delivering pressure fluidto a selector valve by which the pressure fluid is directed to any oneof a plurality of fluid pressure responsive motors operating controlleddevices, the pump or pumps being connected to the selector valve by twoseparate paths, in one of which are arranged pressure accumulatorsstoring pressure fluid for the operation of other controlled devices,and a valve device operated by loss of fluid from the system beingprovided to ment of the float as the liquid level falls causing thewithdrawal of the detent, whereby the plunger is released for movementunder the influence of the spring.

Other objects and features of the invention will be apparent from thefollowing description taken in connection with the drawings forming apart of this specification, and in which:

Figure 1 is a diagrammatical view of a fluid pressure remote controlsystem, embodying the invention;

Figure 2 is a sectional elevation of a reservoir and change-over valvedevice for the system shown in Figure 1;

Figure 3 is a sectional plan view on the line III-III of Figure 2;

Figure 4 is a sectional elevation of an alternative arrangement of thereservoir and changeover valve device;

Figure 5 shows a modified form of float for use in the arrangementshownin Figure 4; and

Figure 6 is a diagrammatical view of a modified fluid pressure remotecontrol system embodying the invention.

Figure 1 showsdiagrammatically a system in which a single engine drivenpump I supplies liquid under pressure to fluid pressure responsivemotors operating any one of four services.

The system is designed for use in an aircraft, and is employed foroperating a retractable undercarriage, flaps, brakes and guns. 1 Theundercarriage is operated by jacks represented at 2, 2, the flaps byjacks represented 'at 3, 3; and the brakes and guns are operated bymotors not shown, receiving liquid respectively from the accumulatorsrepresented at 4 and 5.

The admission of liquid to the undercarriage and flap jacks iscontrolled by a selector valve 6 having separate selecting plungers forthe'undercarriage and flaps, each of which plungers may be moved in twodirections from a neutral position to supply liquid for extending orcontracting the jacks. The liquid from the accumulators 4 and 5 isadmitted to the motors operating the brakes and guns by separate controlvalves (not shown). Thus the undercarriage and flap operations are theprimary services, and the brake and gun operations the "secondary"services.

A reservoir 1 contains a reserve supply of liquid, and to the base ofthis reservoir is secured a valve device 8 to which liquid is deliveredfrom the pump I through a pipe I I. From the valve device 8 lead twopipes l2 and 13, the pipe 12 leading to a non-return valve unit H, fromwhich a pipe l5 leads to the pressure accumulators 4 and 5 and to asecond non-return valve unit l6. The pipe l3 from the valve device 8also leads to the non-return valve unit 16, and a third pipe I1 fromthat unit leads to the selector valve 6, and unit l6 comprising twonon-return valves so arranged that liquid can flow only from pipe 12 orIE to pipe l1, and cannot flow bac into either pipe i2 or pipe 15.

Each of the accumulators 4 and 5 is provided with a cut-oil andby-passvalve, by means of which the liquid flowing in the pipe 15 is divertedinto the accumulator when the pressure therein falls below apredetermined limit, the valve operating automatically when theaccumulator is re-charged to by-pass the liquid, so that it flows on bythe pipe 11 to the selector valve. This valve may be of any desiredtype, an example being that described in the United States ApplicationSerial No. 159,803, filed on August 18th, 1937 (now Patent No.2,184,793).

From the selector valve 6 lead pipes l8, 2|, 22, 23, the pipes 18, 2|leading to opposite ends of the undercarriage jacks 2, 2, and the pipes22, 23 to opposite ends of the flap jacks 3, 3. The selector valve is soarranged that any one of these pipes may be connected to the pipe 11 sothat liquid under pressure is supplied to one end of the jacks of one orother set, the pipe leading to the other ends of these jacks beingconnected simultaneously to a pipe 24 leading from the selector valve tothe reservoir and so permitting the liquid expelled from the jacks toreturn to the reservoir. When the selector valve plungers are in theirneutral positions, the pipes l1 and 24 are connected, so that the liquiddelivered by the pump can circulate idly. None of these features of thevalve 6 are claimed herein, per se; for such claims reference should behad to my Patent No. 2,184,793, above referred to.

A hand pump 26 is provided for loading the accumulators when the enginedriven pump 1 is not working, and also for operating the flap jacks 3 orundercarriage jacks 2 under the same conditions. This hand pump drawsliquid from the reservoir 1 through a pipe 21, and delivers it by a pipe28 to a hand operated valve 3| having two positions. From the valve 3| apipe 32 leads to the non-return valve unit l4, and a second pipe 33leads to the selector valve 6. Thus by suitably positioning the valve3|, the liquid delivered by the hand pump may be supplied through pipes32 and I5 to the accumulators, or through the pipe 33 to the selectorvalve.

It will be observed that there are two paths by which liquid may flowfrom the change-over valve device 8 to the selector valve 6. One path isthrough pipe 2, valve unit 14, pipe l5, valve unit 16 and pipe l1, theliquid then flowing through the cut-out valves of the accumulators, andrecharging these if necessary. The other path is through pipe l3; directto valve unit l6 and through pipe l1. The valve device 8 is so arrangedthat the delivery pipe ll of the pump may be connected to either pipe I201' I3, being normally connected to the pipe l2, and the valve device 8is operated in a manner to be hereinafter described, in the event ofleakage in the system, to disconnect the pipe II from the pipe l2, andconnect the former to the pipe 13.

The pump I, therefore, delivers liquid under normal conditions to thepipe l2, from which it flows to the pipe 15, and loads up theaccumulators 4, 5, flowing on when these are fully loaded, through thepipe l1, selector valve 6 and pipe 24 back to the reservoir 1. Should itbe desired to operate the undercarriage or flaps, for example, to lowerthe undercarriage, the selector valve 6 is operated to connect the pipeI1 to the pipe [8, the pipe 2| being simultaneously connected by thepipe 24 to the reservoir, and the liquid delivered by the pump extendsthe jacks 2, 2, liquid from the other ends of the jacks returning freelyto the reservoir. The selector valve may be arranged to returnautomatically to its neutral position when the lowering of theundercarriage is completed.

Should there be continuous leakage of liquid from the system, thechange-over valve device 8 is operated to disconnect the pipe II fromthe \pipe 12, and to connect it to the pipe 13, thus cutting theaccumulators 4 and 5 out of the circuit, and causing the pump to deliverliquid directly to the selector valve, so that if the leakage is in theaccumulators, or in the cylinders and pipe of the services operated bythe accumulators, which together form a large and somewhat vulnerablepart of the system, the services supplied through the selector valve areable to continue working.

One form of change-over valve device for use in this system is shown inFigures 2 and 3, the valve bodybeing mounted on the base of thereservoir 1 as indicated in Figure 1.

The valve device 8 is formed with a cylindrical bore 34 in which isfitted a valve plunger 35, and ports 36-, 31, 38 in the walls of thebore 34 lead to passages in lateral bosses 4|, 42, 43, drilled andtapped to receive banjo connections 44, 45, 46, to which the pipes i I,I2 and 13 are connected.

The bore 34 is stepped at 41 to provide an end 4 portion 48 of reduceddiameter. The valve plunger 35 has a main diameter which is a slidinglit in the part 48 of the main bore, and from which project collars 5|,52 fitting in the main bore 34, these collars defining an annular spacebetween them. The ports 31 and 36, leading respectively to the pipes l2and I3, are on one side of the bore 34, and are spaced apart, the port36 leading tothe pipe ll being on the'other side of the bore 34, andapproximately midway between the other two ports, so that either port 31or 38 may be connected by the annular space between the collars 5|, 52to the port 36, the other port being cut off. The plunger is shown inthe position in which it connects the ports 36 and 31, that is theposition for normal operation of the system, and it is retained in thisposition by a ball 53 engaging a conical part 54 of the plunger, theball 53 being mounted in an aperture 55 in the side of the part 48 ofthe bore 34, and being held in position by a plunger 56 in turn engagedby a cam 51. The cam 51 is pivotally mounted at 58 between two lugs 61provided in the valve device 8 and'projecting into the reservoir 1, thepivot 58 also carrying an arm 62 on which is mounted a float 63. Aspring 64 mounted in the hollow interior of the valve plunger 35 tendsto move the plunger from the position in which it is held by the ball53, and as soon as the liquid level in the reservoir becomes too low tosupport the float 63, the latter falls,

reservoir 1, the latter being cutaway as shown in.

turning the cam 5'! and releasing the plunger 56,

so that the valve plunger 35, under the influence of the spring 64,forces the ball 53 aside and moves along the bore 34, cutting off theport 36 from the port 31, and bringing into communication the ports 36and 38. The accumulators 4, 5 are then cut off from the pump, asdescribed with reference to Figure 1, and the pump delivers directly tothe selector valve. The valve may be re-set to its initial position whenthe reservoir is refilled and the system repaired, by pushing itinwardly against the spring 64 until the ball 53 again rides down theconical surface 54 and the cam 51 holds it in position. A handle 59 isprovided on'the plunger 35 to assist the resetting operation.

The valve device 8 is formed with a flange 65 by means of which it isbolted to the base oi the Figure 2 to permit a projecting part 66 of thevalve device to project through into the reservoir, and a gasket 61being fitted to render the joint liquid-tight. The bolts 68 securing thevalve device 8 in place also secure a plate II to the inner face of thereservoir bottom, this plate II serving as a mounting for the severalpipe unions for the supply and return pipes.

These unions are five in number (see Figure 3), union 12 being for thepump suction pipe, unions I3 and I4 for the return or exhaust pipes fromthe units fed by the accumulators 4 and 5, union I5 for the suction pipe21 of the hand pump, and union I6 for the return pipe 24 from theselector valve. The union I3, 14 and I6 of the return pipes are providedwith stand-pipes in the reservoir I which extend above the level ofliquid at which the float 63 operates the change-over valve device 8, sothat the liquid remaining in the reservoir after the valve has changedover cannot be lost by leakage through the return pipes. The stand pipes11, I8 rising from unions I4 and 16 are shown in Figure 2, as is alsothe union I5, which has no stand-pipe.

An alternative form of change-over valve device is shown in Figure 4,this form of valve device also being arranged on the base of thereservoir I. This form of change-over valve device comprises a plunger8| working in a bore 82, into which open two ports 83, 84 connected tothe pump delivery, and two ports 85, 86 leading respectively to thepipes I2 and I3 of Figure 1. The plunger carries three seals, shown inthe drawing as rubber rings 81, 88, 9I, so arranged that in one of twoselected positions the port 83 is connected to the port 85, and in theother the port 84 is connected to the port 86, the other pump port beingsealed in each case. The valve plunger 8| is hollow, and inside it ismounted a spring 92 urging it towards the position in which the pumpdelivery port 84 is connected to the pipe port 86, a detent 93 beingprovided to hold the plunger against the spring, in a position in whichthe ports 83 and 85 are in connection with each other. This detent 93 iscarried by a piston 94 moving in a cylinder 95 bolted to the base of thereservoir I, the piston moving in a. direction at right angles to thevalve plunger 8|. In the upper end of the cylinder 95 is a port 96leading to the interior of the reservoir I, and in the cylinder Wallclose to the lower end is a port 91 leading to a passage 98 also openinginto the reservoir. Stand-pipes I8I, I82 of different lengths areconnected to the port 96 and the passage 98, the longer stand pipe I8I.being connected to the port 96. A port I83 in the wall of the cylinder95 leads to the suction orifice of the pump I, and this port is placedin communication with either stand-pipe IN or I82, according to theposition of the piston 94, the port I83 being above the piston when thelatter is in its lower position, and so being connected to the standpipeI 8|. The port I83 is in register with a groove I84 in the piston whenthe latter is in its upper position, said groove being connected by aport I85 to the lower side of the piston, so that the port I83 is thenconnected to the standpipe I82.

A float I86. in the reservoir carries a dependent stem I81 which entersthe stand-pipe IN, the float having on its lower surface a seatingwasher I88 which rests on the upper end of the stand-pipe and closes itwhen the liquid level in the reservoir falls to a sufficient extent.

So long as the liquid in the reservoir I is above the top of thestand-pipe I8I, the float I86 leaves the end of the stand-pipe open, andthe piston 94 remains at the lower end of the cylinder 95, sealing theport 91. The pump suction port I83 is then in communication with thestand-pipe MI, and the detent 93 holds the plunger 8| in the position inwhich the ports 83 and 85 are connected, so that the liquid deliveredbythe pump flows through the pipe I5 (Figure 1) and keeps theaccumulators charged.

If, due to leakage of liquid, the level in the reservoir I falls, thefloat I86 eventually reaches a position in which the seating washer I88closes the top of the stand-pipe I8I. The continued operation of thepump creates a vacuum in the cylinder 95 above the piston 94, with theresult that the piston is drawn along the cylinder until it exposes theport 91, and at the same time withdraws the detent 93 to release theplunger 8|, which is moved by the spring 92 to close oif the pumpdelivery port 83, and to connect the ports 84 and 86. The liquid fromthe pump then flows to the selector valve without passing through thepipe I5. A by-pass port III is provided between the extreme top of thecylinder 95 and the port I83, so that the suction is able to lift thepiston 94 until the groove I84 registers with the port I83, and liquidcan flow to the pump through the lower stand-pipe I82, the passage 98,cylinder 95, groove I84 and port I83, thus keeping'up the supply fromthe liquid remaining in the reservoir.

Figure 5 shows a modified form of float which may be used instead ofthat shown in Figure 4. This float comprises a hollow annular body II2the central passage through which is closed at its upper end and carriesat seating I I3 of soft material such as india rubber. The lower end isprovided with a plurality of inwardly projecting spring fingers H4, andthe stand-pipe I8I has a collar I I5 brazed or sweated on to its upperend, the spring fingers 4 being arranged to engage beneath the collar H5and prevent the float from leaving the stand-pipe. An eyelet I I6 ismounted in the top of the float for the attachment of a chain or wirewhich enables the float. to be pulled off the stand-pipe when itsremoval is required for cleaning or inspection.

Each of the accumulators 4 and 5 is connected to the motors of theservices which it operates, through a control valve having twopositions, in one of which the pressure accumulator is connected to themotors, whilst in the other position the motor is connected to anexhaust passage (I I! or H8 in Figure 1) leading to the reservoir I.These control valves and the motors of the accumulator-operated servicesare not shown on the drawings.

It will be understood that any number of primary services and any numberof secondary services may be operated by the system according to thisinvention, the primary services being operated directly by the pumpthrough a selector valve, or by accumulators in the same manner as thesecondary services. It may even be found desirable to operate somedevice, such as a retractable undercarriage, either by an accumulator,as a "secondary service, or directly by the pump as a "primary service,"the accumulator normally serving to operate the undercarriage, whilstthe direct operation is available in an emergency.

Figure 6 shows schematically the manner in which an auxiliary pressureaccumulator may be added to the system of Figure 1 for the purpose ofassisting in at least the lowering operation of the undercarriage.

Such an additional accumulator, as indicated at I22 in Figure 6, mayhave connection with pipe I! (corresponding to pipe ll oi. Figure 1) byway of a connecting conduit IIa in which is located a non-return valveI24 and a manually controllable valve I25; 9. similar non-return valveI26 being fitted in pipe I I to prevent reverse flow in the latter.Numeral la in Fig. 6 identifies the plunger corresponding to thelefthand plunger of the valve 6 of Fig. 1, said plunger being the onecontrolling operation of the undercarriage jacks 2, 2.

The control rod I25a of the valve I25 has a lost motion connection,represented diagrammatically at I21, with the hand lever I28 01 theselector valve 5, the arrangement being such that the selector valve maybe operated to raise the undercarriage whilst leaving the valve I25closed, so that the raising operation is carried out by pressure liquidcoming directly from the pump I. When the selector valve is operated tolower the undercarriage, however, the valve I25 is opened, and thepressure in the accumulator I22 is brought into use. Because of thenon-return valves I24, I26, pressure from the accumulator I22 can lowerthe undercarriage even if there is a leak in the pipe I1, and similarlyno damage to the accumulator I22 can aiIect the operation of theundercarriage by pressure liqui flowing directly from the pump I.

By controlling the valve I25 independently of the selector valve 6, theaccumulator pressure may be used at will to assist or replace the directflow of liquid from the pump, and in such case the accumulator may beused to assist in raising the undercarriage.

The pressure accumulators actuating the secondary services may bearranged in any part of the main pump circuit, the change-over valvedevice being suitably arranged to isolate that part of the circuit. Forexample they may be arranged in the return pipe 24 between the selectorvalve 6 in Figure 1 and the reservoir I. The main services will thenhave priority of operation if one ,is selected whilst one or more of theaccumulators is partially discharged, instead of being delayed until allthe accumulators are fully charged, as is the case in the systems shownin Figures 1 and 6.

The system is capable of use for other purposes than' aircraft controls,being readily adapted for use in any position where a plurality ofdevices are to be controlled by liquid pressure means.

merous other applications that will readily occur to persons skilled inthe art. The invention is, therefore, to be limited only by the scope ofthe appended claims.

What I claim is:

1. A fluid pressure remote control system comprising a source ofpressure fluid, fluid pressure responsive motors, separate pathsconnecting the source of pressure fluid to the motors, a spring loadedplunger controlling said paths, stop means keeping the plunger in aposition to connect the source of pressure fluid to one of said pathsand means operated by the level of fluid and actuating said stop meansto connect, the source 01' pressure fluid to the other of said paths.

2. A fluid pressure remote control system according to claim 1,comprising a float, a cam actuated by the float and detent meansoperated by the cam and controlling the position of the plunger.

, 3. A fluid pressure remote control system according to claim 1,comprising a plurality of return flow conduits terminating in saidreservoir, a float in the reservoir operating the stop means, and meansincluding a stand-pipe for each of said return flow conduits to preventloss of fluid from the reservoir by way of any of said return flowconduits, each of said stand-pipes having a height which is above thelevel at which is operated the float.

4. A fluid pressure remote control system comprising a power pump, fluidpressure responsive motors, a reservoir, separate paths connecting thepower pump to the motors, a spring loaded plunger controlling-the paths,a connection between the reservoir and the suction port of the pump, achamber forming part of said connection, a piston in said chamber, adetent on the piston engaging with the plunger Ior keeping it in aposition to connect the pump to one of said paths, a stand-pipe in thereservoir connected to said chamber, a float adapted to shut off saidstand-pipe and thus induce a vacuum in the chamber for withdrawing thedetent from the plunger, and connect the pump to the other of saidpaths.

5. A fluid pressure remote control system comprising a power pump, fluidpressure responsive motors, a reservoir, a connection between thereservoir and .the suction port of the pump, a chamber forming part ofsaid connection, a piston in said chamber, a stand-pipe in the reservoirconnected to the chamber above said piston, a

between the control member and the valve controlling the delivery of theaccumulator, and a lost motion in said operating connection.

7. A fluid pressure remote control system comprising a reservoir, asource of pressure fluid, fluid pressure responsive motors, connectionsbetween the source of pressure fluid and the motors, a selector valveadapted to connect the source of pressure fluid to any of said motors,

. separate paths between the source of pressure fluid and the selectorvalve, accumulator means arranged on one of said paths, a spring loadedplunger controlling said paths, stop means re=- taining the plunger in aposition to connect the source of pressure fluid to said one path and afloat in the reservoir actuating said stop means upon the fall of liquidlevel in the reservoir, to cut oil the path in which the accumulatormeans is arranged and connect the source of pressure fluid to the otherpath.

SYDNEY MACDONALD PARKER.

